1. Field of the Invention
The present invention relates to a friction clutch having a housing arrangement connectable to a drive element for rotation in common therewith about an axis of rotation, a plurality of first friction disks connected to the housing arrangement such that the first friction disks are fixed with respect to rotation relative to the housing arrangement and axially movable relative to the housing arrangement, a plurality of second friction disks connected to a hub such that the second friction disks are fixed with respect to rotation relative to the hub and axially movable relative to the hub, wherein the hub has a plurality of radially outward-projecting rotational connection arms which engage with the second friction disks for rotation in common with the hub, and a force-exerting arrangement exerting a force for urging the first friction elements into frictional contact with the second friction elements.
2. Description of the Related Art
A friction clutch is known from German patent document DE 198 21 654 A1, in which three ring-shaped, disk-shaped friction elements are connected nonrotatably to a hub. For this purpose, the hub has radially outward-projecting rotational connection arms, which thus give the hub an essentially star-like configuration. The friction elements connected to this hub have corresponding, inward-projecting rotational connection arms, so that in this way they can be connected to the hub in a way which does not allow relative rotational movement but which does allow movement in the axial direction.
A friction clutch is known from US Reissue Application RE 36,363, in which the hub also has a plurality of radially oriented rotational connection areas or rotational connection arms proceeding from a radially inner, ring-like area for the friction disks to be connected to it. The axial dimension of the rotational connection arms corresponds to the radial dimension of the ring-like area of the hub situated radially inside them. In the areas between directly adjacent rotational connection arms, walls are provided to bridge the gaps in the circumferential direction. These walls are much thinner in the axial direction than the rotational connection arms and are approximately centered relative to the axial direction with respect to the rotational connection arms. These walls are located between two friction disks to be connected nonrotatably to the hub and extend radially outward to the exact same extent as the rotational connecting arms and retain the hub axially with respect to the friction disks.
German Patent Document DE 198 10 981 A1 discloses a friction clutch, i.e., a hub for such a clutch, in which the axial fixation of the hub with respect to the friction disks to be connected nonrotatably to it is also accomplished in the radial area of the rotational connection arms. For this purpose, it is possible, for example, to provide a circumferential web or a circumferential wall on one axial side of these rotational connection arms and to provide a securing disk on the other axial side.
In the new drive systems being developed for use especially in racing vehicles, but also to an increasing extent in ordinary vehicles, the torques which must be transmitted are continually increasing. These torques must be transmitted via the friction clutches, thereby subjecting the friction clutches to very high loads. This leads to stability problems, especially in the area where various components are connected to each other for the transmission of torque.